In CMOS image sensors, although a rolling shutter operation is basic architecture, a CMOS image sensor that has a function of global electronic shuttering (whole-pixel-simultaneous electronic shuttering) and reset-noise removing is proposed (see patent literature (PTL) 1). As the CMOS image sensor that has the above whole-pixel-simultaneous electronic shuttering function, in PTL 1, a part of the CMOS image sensor is implemented by CCD structure, and in order to hold charges, the realization of lower dark current characteristic is tried with CMOS capacitors of buried configuration.
Alternatively, CMOS image sensors that hold charges by using accumulation diodes of buried configuration, without using the CCD structure are proposed (see PTLs 2 and 3). In the CMOS image sensor disclosed in PTL 2, charges are transferred by using a depletion potential difference generated by changing n-type doping concentrations of photodiode and the accumulation diode. In the CMOS image sensor disclosed in PTL 3, by controlling shuttering gate, charges are shared in the two diodes of photodiode and the accumulation diode, and a part of charges generated in the photodiode is moved to the accumulation diode, and consequently, the electronic-shuttering operation is carried out, even if there is no difference of the depletion potential as the photodiode and the accumulation diode have the same doping concentration.